Pregnancy Isn't the Only Risk That Comes With Quitting Your Birth Control

Quitting your birth control is a big decision, perhaps even a life-altering one. But while some consequences of going off the pill are well known — hello pregnancy! — there's one side effect that might surprise you. Women who stop taking the pill also experience a major drop in their vitamin D levels, according to a new study published by The Endocrine Society.

Researchers looked at nearly 1,400 women, taking blood samples while they were on birth control and then again after they quit taking it. They found the women experienced a 20 percent decrease in levels of vitamin D after stopping their hormonal birth control. The estrogen in the pills, they speculated, helps preserve vitamin D in the body.

"Our study found that women who were using contraception containing estrogen tended to have higher vitamin D levels than other women," said the study's first author, Quaker E. Harmon, M.D., Ph.D., of the National Institutes of Health's (NIH) National Institute of Environmental Health Sciences, in a press release. He added this was true even after they adjusted for things like supplement use and sun exposure.

"Our findings indicate women may run the risk of developing vitamin D deficiency just when they want to become pregnant," Harmon said. "For women who are planning to stop using birth control, it is worth taking steps to ensure that vitamin D levels are adequate while trying to conceive and during pregnancy."

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